Screen printing is a process for applying an ink or other substances to a variety of substrates. A printing press is used to apply the ink to the substrate in a process referred to as registration.
A screen is placed in the printing press. The screen has a screen frame with a screen mesh. Ink is forced through the screen and onto the printing surface of the substrate. Multiple colors of ink may be applied separately. Typically, the ink is applied, either manually or by an automated machine, with a squeegee that puts pressure against the screen mesh to keep the screen mesh in contact with the underlying substrate.
FIG. 1 depicts an example of a manual printing press 102. The printing press 102 has a frame 104 to which a center shaft 106 is attached. A pallet carousel 108 and a screen frame carousel 110 may be independently rotated about the center shaft 106 either clockwise or counterclockwise.
The pallet carousel 108 includes one or more pallet support arms 114 extending from the central portion 112 of the pallet carousel 108. At the end of each pallet support arm 114 is a pallet 116. A substrate 118, such as a shirt, other textile, or other substrate, is placed on, over, or around the pallet 116 so that ink or another substance may be applied to the substrate.
The screen frame carousel 110 includes one or more print head assemblies 120 extending from the central portion 122 of the screen frame carousel. Each print head assembly 120 has a hinge 124 connecting one or more screen frame clamps 126 to the central portion 122 of the screen frame carousel 110.
A screen 128 having a screen frame 130 and a screen mesh 132 fits at or in the screen frame clamp 126. Although the clamps 126 are depicted as clamping on the sides of the screen frame 130, other clamping systems may be used, such as front clamps and/or rear clamps.
One or more clamp adjusters 134 are used to tighten the screen 128 within the screen frame clamp 126, and one or more print controls 136 adjust the alignment of the clamped screen 128 within the screen frame clamp 126. In one example, one or more controls 136 are used to adjust the screen 128 in the X axis and Y axis relative to the print head assembly 120 so that ink may be applied onto the substrate 118 at precise points on the substrate.
A squeegee 138 is used to pull ink or another fluid or substrate across the screen mesh 132. Typically, the squeegee 138 has a frame 140 and a blade 142.
In operation, a user places a screen 128 in a print head assembly 120 and adjusts the clamp adjusters 134 so that the screen fits tightly within the screen frame clamps 126. The user places a garment, cloth, or other substrate 118 on a pallet 116. The user may rotate the print head assembly 120 with the screen 128 and/or the pallet 116 having the substrate 118 so that the screen and print head assembly are properly located above the substrate. The user then lowers the print head assembly 120 with the screen 128 so that the screen mesh 132 is in contact with, or directly above, the substrate 118. Ink (not shown) or another fluid is placed on the screen mesh 132. A squeegee 138 then is used to pull the ink across the screen mesh 132 and onto the substrate 118. The user must apply at least some downward pressure on the squeegee 138 while pulling the squeegee across the screen mesh 132 in order to force the ink through the screen mesh. The user generally applies pressure to the squeegee at an angle so that the blade of the squeegee forces the ink through the screen mesh 132. The downward angled pressure causes the screen mesh 132 to contact the substrate 118 while forcing the ink through the screen mesh, thereby applying the ink onto the substrate.
In the above example, the user has to judge how much pressure is to be applied with the squeegee 138 and the angle at which the blade 142 is to be applied to the screen mesh 132 each time the user pulls the squeegee over the screen mesh. The amount of pressure and the angle applied by the user to the squeegee 138 and therefore to the screen mesh 132 may therefore be different each time the user pulls the squeegee across the screen mesh.
As the user continuously pulls the squeegee 138 across the screen mesh 132, either because multiple colors are to be applied onto the substrate 118 and/or because a design is to be applied to multiple substrates, the user tends to tire. Therefore, the user tends to misjudge the actual pressure and angle being applied to the squeegee 138 and therefore to the screen mesh 132.
Additionally, since the width of the blade 142 of the squeegee 138 is less than the width of the screen mesh 132, the user must attempt to maintain the blade in a substantially horizontal plane as the user pulls the squeegee across the screen mesh. However, users to tend to pull the squeegee at an angle in the horizontal plane such that either the left or right side of the blade 142 is pulled across the screen mesh 132 before the other side. This causes ink to be applied onto the substrate 118 in an uneven manner. This uneven registration typically is exacerbated when the user tires or otherwise when multiple pulls are required.
Moreover, a variance in the vertical pressure and angle and the horizontal angle typically occurs when different users operate the press. Other variances also occur when one or multiple colors of ink are applied for a design on a single substrate or multiple substrate. Variances in the registration of colors for a substrate may result in one color running into or over another color of the same design.
Further, the printing industry typically describes the type of pressure to be applied to a squeegee 138 as a “medium” pressure or similar description and at a 57 degree or 60 degree angle. It is difficult for a user to judge whether such a pressure is a “medium” pressure and if the pressure is applied at the specific 60 degree angle or other angle.
Fully automatic presses have been developed to solve some of the above-referenced issues. However, the automatic presses typically are significantly more expensive than a manual press, require more maintenance than a manual press, and require more expensive maintenance than a manual press. Therefore, many users continue using the manual presses instead of purchasing and using the fully automated presses. Often, smaller businesses use manual presses or any business having a smaller number of shirts or other substrates to be applied in a run use manual presses. The manual press industry and the fully automated industry have developed along different paths, and technology associated with the fully automated presses typically does not apply to the technology associated with the manual presses.
Therefore, systems and methods are desirable that enable a user to semi-automate the manual press and the manual press process. Systems and methods are needed to enable a user to apply a squeegee to a screen mesh at consistent horizontal and vertical angles and using a consistent pressure for each registration so that variances in registrations are decreased.